Improvement in saw-mills



UNI-iran STATES PATENT FFICE.

lV. W. EWING, OF MAHONING, PENNSYLVANIA.

IMPROVEMENT IN SAW-MILLS.

Specification forming part of Letters Patent- NO. 59,200, dated October 30, 1866.

To all whom it may concern:

Be it known that I, W. W. EWING, of Mahoning, in the county of Indiana and State of Pennsylvania, have invented an ImprovedY Saw-Mill; and I do hereby declarethat the following is a full and exact description thereof, reference being had to the accompanying drawings, making part-of this specification- Figure l representing a plan ot' so much of the frame-work of a saw-mill and so much of the working parts thereof as are necessary to show my improvement; Fig. 2, a longitudinal vertical section of the frame-work, and representin g most ot' the workin g parts in elevation; Figs. 3, 4, 5, 6, 7, and S, sections and views of detached parts, fully delined by the letters of reference, which indicate corresponding parts in all of the figures.

My improvements have reference and application to the method oi' hanging the'saw or saws of a gang between vibratory tensionbeams, thereby dispensing with the employment of a sliding saw-gate and its frame, with all the disadvantages of that method of han ging saws.

Let A A A represent the timbers of a sawmill arranged for the reception of my improvements. Two pairs of strong cross-timbers, a' a, are set, one above the other, at a proper distance for receiving sets of clamp-bars B B, between which the several pivot-blocks C C, in

which vibrate the rock-shafts D D of the ten-A sion-beams F F F F, are held. The situation of the timbers a a c c is indicated in Fig. 2.

The pivot-blocks C G have shauks c c oi' dovetail form,"and the inner sides of each pair of clamp-hars B B have corresponding forms to lit the same, as shown in the enlarged detail view, Fig. 3, so that when the bars are tightened against these shanks the blocks are held very securely in all directions. The clampbars are thus tightened by means of counterwedges or keys b l), Fig. 3, driven into the mortises in the timbers a c outside of the tenons ot' the bars which it in said mortises. These keys not only serve to clamp the pivotblocks tightly, but enable the blocks to be adjusted sidewise in either direction, and by loosening the keys and sliding the pivot-blocks endwise between the bars the said blocks are by tightening the keys. By these means provision is made for the complete adjustment of the position of the tension-beams F F F F and -of the saw G mounted between them at the front end.

Since one object to be attained in this construction and operation of mills is to lessen the friction with which the saw is run, the rockshafts D D of the vibratory beams F F F F are provided with hardened knife-edge pivotjournals d d cl d, which rest in V -shaped notches of the bearings e e e e on the pivotblocks, substantially as shown in the detail view, 4. The angle of the pivot-journal is less than that of the V-shaped notches in which they vibrate, so as to allow the requisite vibratory movement without restraint or friction. .Onerock-shaft is directly over the other and. parallel with it, to insure a free vibration of both pairs of tension-beams together.

' Each pair of vibratorytension-beams F F is strongly secured to their rock-shaft, about two-thirds or" their length from the saw end to the other end, and where they are attached to their rock-shaft they are separated a considerable distance, converging thence to the saw G, which is clamped between their adjacent surfaces at their ends, there being only washerplates between to prevent too much wear and friction. This arrangement of the vibratory beams braces their position against any side swayingof the saw, which must not be allowed.`

The saw G is hung at each end on apivot-bolt, H, which extends horizontally through the adjacent clamping ends of the vibratory beams, and is secured there by a nut screwed upon each end against the outer sides of the said beams. The bolts are square or angular where they go through the beams, as shown at f f, Fig. 6, and it the holes in the beams ot' corresponding form. This prevents the turning of the bolts, which are grooved out transversely around their middle, as shown at h, Fig. 6, in such a manner as to present a knifeedge form in cross-section at the outer point, (highest or lowest, ,as the case may be,) as seen in Fig. 5. This knife-edge lits into a V-shaped notch, g, in the saw, the angle of which isalittle greater than that of the knife-edge of the bolt, so that there may be free angular vibration of the saw on the bolt, since, as the tension-beams.

vibrate, the saw necessarily varies its angle in respect thereto. The notch or aperturevg in the saw is enlarged inside of the V-shaped bearin g, so as to allow the insertion and withdrawal of the pivot-bolts H H. The knifeedges are of steel, hardened, or iron, casehardened or chilled, in order to prevent rapid wear.

The vibration of the tension-beams so as to give the required strokes of the saw may be properly effected by a pitlnan, N, communieating between the lower pair of tension-beams and a crank, 0, of the driving-shaft. This is so arranged that when the saw is brought to the bottom of its stroke the vibratory beams are horizontal, or nearly so, so that the cut or rake7 of the saw is produced by the consequent forward thrust of the beams as they descend to a horizontal position. If the rake -is too great by this movement, it is lessened by setting the upper end of the saw farther back, and vice versa.

In order, also, to avoid friction as much as possible in the connection between the pitman and the vibratory beams, there is a cross-head,

L, attached to the upper end of the pitman,l

and provided with knife-edge pivot-arms l l, which are held in enlarged or loose bearings iin the lower ends of bolts I I, extending upward, respectively, through the lower tension-beams, F F, as shown in Fig. 7. This allows the tension-beams to be adjusted or moved together or apart without interfering with the pitman-joint. There is a bearingblock, m, with a knife-edge, n, secured to the under sides of the tension-beams; and this knife-edge iits in a notch, o, 'of a larger angle in the upper end of the pitman cross-head L; and there is a notch in the wedge of the bear-4 ing, receiving a wedge'bearing on the crosshead, the two sets of edges and notches being at right angles, so as to keep the bearing-connection in one fixed central position, and at the same time allow the utmost freedom of vibration and produce the least possible friction.

The rear'ends of each corresponding upper and lower pair of tension-beams are connected bya tension-rod, S, which is hung to each beam by a stirrup, l?, having a hardened knifeedge bearing, p, Fig. 8, that ts in a V-shaped notch, r, of a larger angle in a bearing-plate, It, attached to each beam. This, as in other cases before described, allows freedom of movement and vibration with very little friction. The tension-rod S has a swivel-joint, n, eonneetin g it with one stirrup, anda screw-thread, t, turning in a female screw in the other stirrup; or right and left screws may serve for both connections. The rod has a square portion, s, Fig. 2, serving to grasp it, with a wrench to turn it with.

When the .saw is removed for sharpening, or

The many advantages of this method of hanging and driving the saws of saw-mills are apparent without specific enumeration. A much more rapid movement may be given to the saws than with a saw-gate, and the superiority in respect to freedom of movement and from friction, and less liability to breaking and getting out of order, is very marked. f

What I claim as my invention, and desire to secure by Letters Patent, is-

1. The combination and arrangement of the two pairs of converging vibratoryr tensionbeams F F, clamping the endspof the saw between their converging ends, substantially as and for the purpose herein specified.

2. The combination of the pivot-blocks C C, having dovetail Shanks, with the adjustable clamp-bars B B, having corresponding forms to iit the Shanks of the pivot-blocks, substantially as herein set forth.

3. The method ofhanging the saws between the tension-beams by the V-shaped notches therein and the peculiarly-formed pivot-bolts H H, substantially as and for the purposes herein described.

i The above specification of my improved sawmill signed by me this 15th day of September,

W. W. EWING. Vitnesses:

JAMES SPENCER, SAMUEL EAKMAN. 

